Projection welded panel spacer and method for making the same

ABSTRACT

A method for making a spacer assembly comprises: forming a plurality of projections along an edge of a portion of sheet metal; roll forming the portion of sheet metal into a tubular configuration; positioning the roll formed portion of sheet metal and a metal base member to which the roll formed portion of sheet metal is to be welded in a discharge welding apparatus having a pair of electrodes so that the projections of the roll formed portion of sheet metal contact a surface of the metal base member; providing a force so that the projections are disposed in forcible engagement with the surface of the metal base member; and supplying an electrical current between the pair of electrodes and through the roll formed portion of sheet metal and the metal base member so that the projections reach a molten metal stage and are subsequently solidified to enable the roll formed portion of sheet metal to be welded to the metal base member.

This non-provisional patent application claims priority from and thebenefit of provisional patent application serial No. 60/066,105 filedNov. 17, 1997.

FIELD OF THE INVENTION

The present invention relates to spacers used in motor vehicle bodies.

BACKGROUND OF THE INVENTION

In the automotive industry, spacers are used for various applications.For example, spacers have been used to support or reinforce a crossframe support structure which supports a truck bed on the vehicle frame.Conventionally, such spacers would be cut from a pipe or tube stock andmig welded to a plate member and positioned to assist the cross framesupport in supporting the truck bed on the vehicle frame.

A shortcoming of this prior art construction is that mig weldingrequires extreme heat, which causes deformation of parts. In addition,mig welding is a relatively slow, cumbersome, and inefficient operation.In addition, the conventional spacers are not cost-effective from amaterials point of view, as they utilize relatively expensive weldedseam or seamless tubing.

It is an object of the present invention to overcome the disadvantagesof the prior art noted above.

Accordingly, the present invention provides a method for making a spacerassembly comprises: forming a plurality of projections along an edge ofa portion of sheet metal; roll forming the portion of sheet metal into atubular configuration; positioning the roll formed portion of sheetmetal and a metal base member to which the roll formed portion of sheetmetal is to be welded in a discharge welding apparatus having a pair ofelectrodes so that the projections of the roll formed portion of sheetmetal contact a surface of the metal base member; providing a force sothat the projections are disposed in forcible engagement with thesurface of the metal base member; and supplying an electrical currentbetween the pair of electrodes and through the roll formed portion ofsheet metal and the metal base member so that the projections reach amolten metal stage and are subsequently solidified to enable the rollformed portion of sheet metal to be welded to the metal base member.

It is a further object of the invention to provide a spacer thataddresses the problems noted above. In accordance with this object, thepresent invention provides a projection welded panel spacer, comprisinga metal base member defining an opening, and a sheet metal portion rollformed such that two opposite edges of the sheet metal portion aredisposed in parallel adjacent relationship to one another so as toprovide the sheet metal portion with a tubular configuration. The rollformed sheet metal portion has a plurality of stamped projections formedalong a third edge thereof weldedly connected to the metal base member.A bore defined by the tubular configuration of the roll formed sheetmetal portion is generally aligned with the opening in the metal basemember.

It is a further object of the invention to provide a vehicle truck bedthat incorporates the spacer discussed above. In accordance with thisobject, the present invention provides a vehicle truck bed comprising atruck bed panel, a vehicle frame structure, and a frame support disposedbetween the truck bed and the frame structure for mounting the truck bedpanel on the frame structure. A fixing structure fixes the truck bedpanel to the vehicle frame structure. The fixing structure includes ametal base member defining an opening and mounted on the cross member,and a sheet metal portion roll formed such that two opposite paralleledges of the sheet metal portion are disposed in parallel adjacentrelationship to one another so as to provide the sheet metal portionwith a tubular configuration. The roll formed sheet metal portion has aplurality of stamped projections formed along a third edge thereofweldedly connected to the metal base member. A bore defined by thetubular configuration of the roll formed sheet metal portion isgenerally aligned with the opening in the metal base member. A fastenerextends through an opening in the truck bed, an opening in the framestructure, the opening in the metal base member, and the bore so as tosecure the truck frame to the truck bed panel.

These and other objects, features, and advantages of this invention willbecome more apparent from the following detailed description when takenin conjunction with the accompanying drawings which illustrate, by wayof example, the principles of this invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view of a projection welded panel spacer inaccordance with the present invention shown in operative relationbetween a truck bed panel and a cross frame support;

FIG. 2 is a schematic view showing the progression of sheet metalthrough a progressive die structure to form the spacer tube inaccordance with the method of the present invention;

FIG. 3 is a sectional view taken through the line 3—3 in FIG. 2;

FIG. 4 is a sectional view taken through the line 4—4 in FIG. 2;

FIG. 5 is a sectional view taken through the line 5—5 in FIG. 2;

FIG. 6 is a sectional view taken through the line 6—6 in FIG. 2;

FIG. 7 is a sectional view taken through the line 7—7 in FIG. 2;

FIG. 8 is a perspective view of the spacer tube in its form immediatelyafter formation in the progressive die and mounted upon a base plate towhich the spacer tube is to be projection welded;

FIG. 9 is a schematic representation of the projection or resistancewelding operation in which the spacer tube is welded to the spacer tubebase plate;

FIG. 10 is a perspective view of an oval spacer tube in conjunction witha spacer tube base plate to which the spacer tube is to be projectionwelded to form a panel spacer in accordance with a second embodiment ofthe present invention; and

FIG. 11 is a schematic representation of a projection or resistancewelding operation in which the spacer tube is simultaneously welded tothe spacer tube base plate and an upper metal plate in accordance with athird embodiment of the present invention;

FIG. 12 is a cross-sectional view of a projection welded panel spacer inaccordance the present invention shown in operative relation with across frame support and connecting a truck bed panel with a vehicleframe structure;

FIG. 13 is a schematic view showing the progression of sheet metalthrough a progressive die structure to form the spacer tube inaccordance with another embodiment of the method of the presentinvention;

FIG. 14 is a sectional view taken through the line 14—14 in FIG. 13;

FIG. 15 is a sectional view taken through the line 15—15 in FIG. 13;

FIG. 16 is a sectional view taken through the line 16—16 in FIG. 13;

FIG. 17 is a sectional view taken through the line 17—17 in FIG. 13; and

FIG. 18 is a schematic representation of the projection or resistancewelding operation similar to that depicted in FIG. 9, but illustratingan upper electrode which need not be particularly adapted to the shapeof the roll formed tubular member.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS ILLUSTRATED IN THEDRAWINGS

Referring more particularly now to the drawings, there is shown in FIG.1 panel spacer, generally indicated at 10, being used in combinationwith a cross frame support, generally indicated at 11, and a truck bedpanel, generally indicated at 14.

The panel spacer 10 includes a spacer tube 12 welded at its lower end 15to a metal base plate member 16. The panel spacer 10 further includes afixing assembly, preferably in the form of a bolt assembly indicated at18. The bolt assembly 18 preferably includes a carriage bolt 20, awasher 22, and a nut 24 threaded securely to the threaded portion of thecarriage bolt 20.

In the embodiment shown, the panel spacer 10 preferably includes anupper metal member which closes-off or “caps” the cross frame supportstructure 11. The upper metal member is preferably in the form of aplate 26 and facilitate securement of the truck bed panel 14 to thecross frame support structure 11. The upper metal member or plate 26need not be fixed to the upper end spacer tube 12, and may simply restthereupon. It is contemplated, however, that this plate 26 may be fixedby conventional welding.

Preferably, the spacer tube 12 has a generally cylindricalconfiguration, although the present invention contemplates tubulararrangement of other configurations, such as one with a squaredconfiguration. The carriage bolt 20 extends through a central bore 28through the spacer tube 12. In addition, the lower end 15 of the spacertube 12 which is welded to the metal base plate member 16, as will bedescribed in greater detail later, is disposed in surrounding relationto an opening or hole 30 in the base plate 16, so that a threadedportion of the carriage bolt 20 is disposed beyond the longitudinalextent of the spacer tube 12 to receive the nut 24.

In the arrangement shown, the spacer tube 12 and the base plate member16 welded thereto are dropped as a unit into the well or U-shapedcross-sectional configuration of the frame support 11, so that thebottom surface of the base plate member 16 can be spot welded to thebottom wall 34 of the frame support 11. The hole 30 in the base platemember 16 is aligned with a hole 36 in the bottom wall 34 of the framesupport 11 before the base plate member 16 is spot welded to the wall34.

After this welding operation, the cross frame cap 26 is mounted ontolaterally outwardly projecting flanges 38 and 40 of the frame support 11and spot welded thereto. The cap 26 has an opening 44 which is alignedwith the openings or holes 30 and 36 prior to spot welding the cap 26 tothe flanges 38 and 40. Next, the truck bed panel 14 is mounted on thecross frame cap 26. The bed panel 14 has an opening 46 which is inalignment with the openings 44, 30 and 36. The cross frame cap 26provides a support surface for the truck bed panel 14.

Next, the carriage bolt 20 is passed through the openings 46, 44, 30,and 36 until the head 48 of the carriage bolt 20 engages the uppersurface of the truck bed panel 14. At this point, the threaded portionof the bolt 20 has passed through the spacer tube 12, through the baseplate member 16, and through the lower wall 34 of the frame support 11.The nut 24 is then secured to the threaded portion of the carriage bolt20 and tightened in place.

By providing the panel spacer 10, the tightening of the nut 24 will notcrush in or indent the truck bed panel 14 when the nut 24 is tightenedto a significant extent.

Referring now to FIGS. 2-9, there is showing a method of manufacturingthe panel spacer 10 in accordance with the principles of the presentinvention.

FIG. 2 shows the manner in which a strip of sheet metal is manipulatedthrough a progressive die to form the spacer tube 12 with a series ofcircumferentially spaced projections along its lower edge. In a firstdie operation, a strip of sheet metal 50 is punched to form a straightforward edge 52 and a rearward edge 54 having a plurality of dependingprojections 56. This first stamped configuration 58 remains connectedwith the preceding strip of material 50 by a small interconnecting stripportion 60 at one of the corners of the material.

FIG. 3 is a cross-sectional view taken through the line 3—3 in FIG. 2 inthe direction transverse to the direction of sheet metal movementthrough the progressive die. As shown in FIG. 3, the initial stamping 58has a substantially flat crosssection.

Referring back to FIG. 2, it can be appreciated that in a subsequentconfiguration 64, achieved by the progressive die, a longitudinal edge62 which extends in a longitudinal direction perpendicular to edges isslightly curled. This can be appreciated more fully from FIG. 4, whichis a cross-sectional view taken through the line 4—4 in FIG. 2.

A subsequent configuration 66 of the sheet metal is shown in FIG. 2. Ascan be appreciated from the cross-sectional view of FIG. 5, takenthrough the line 5—5 in FIG. 2, the sheet metal is punched into asubstantially J-cross-sectional configuration.

Referring back to FIG. 2, the sheet metal is worked into the nextconfiguration as indicated at 68, and is generally cylindrical in form.As can be appreciated from FIG. 6, which is a cross-sectional view takenthrough the line 6—6 in FIG. 2, the generally cylindrical configuration68 has an overlapping or extended portion 70 which extends beyond theedge 62.

Referring back to FIG. 2, a final configuration 72 is provided. Thefinal configuration 72 is substantially cylindrical in form. As can beappreciated from FIG. 7, which is a cross-sectional view taken throughthe line 7—7 in FIG. 2, the end portion 70 as shown in FIG. 6 is cut offfrom the final configuration so that an opposite edge 74 of the sheetmetal is disposed in adjacent relation to the edge 62. While these edges62, 74 may subsequently be brought into contact, this is not required,as these edges will not be seam welded to one another.

As can also be appreciated from FIG. 2, the connecting portion 60 whichattaches to each portion of sheet metal to the previous portion of sheetmetal to be formed into a spacer tube, is dislodged and discarded.

Referring now to FIG. 8, it can be appreciated that the generalcylindrical configuration 72, which eventually forms the spacer tube 12,is placed upon the base plate 16 in accordance with the method of thepresent invention.

As is illustrated in the cross-sectional view of FIG. 9, the tubularcylindrical sheet metal configuration 72 and the base plate 16 areprojection welded to one another in a projection welding operation. Theprojection welding operation is a form of resistance welding in whichthe tubular cylindrical member 74 and base plate 16 are positioned in adischarge welding apparatus including a vertically movable upperelectrode 80, and a stationery lower electrode 82. The tubular component72 is forced against the base plate 16 under pressure applied bydownward movement of the upper movable electrode 80. An electricalcurrent is then passed between the upper movable electrode 80 and thelower stationery electrode 82. This causes the projections 56 to heatrapidly due to their relatively small surface areas in contact with thebase plate 16. As the electrical current is passed through theprojections 56, they reach the molten metal stage, as does a smallportion of the base plate 16 which directly contacts the projections 56.The pressure applied by the upper movable electrode 80 then furtherforces the two components together and holds them in place until themolten metal fuses and cools forming a single welded component. Thissingle component constitutes the spacer 10 and base plate 16 illustratedin FIG. 1.

Shown in FIG. 10 is an alternate configuration for a tubular member, asgenerally indicated at 90, which is to be welded to the base plate 16.As shown, the tubular member 90 has a generally oval configuration.

In accordance with the present invention, a projection welded spacerwhich includes a spacer tube and base plate is formed. Because aresistance weld is used to weld the base plate 16 to the spacer tube 12,less heat is employed, causing little or no warping of the mountingsurfaces. In addition, the quality of the resulting part is superior incomparison with the conventional systems in which a spacer tube is migor arc welded to a base plate 16, as these welding operations arerelatively messy and more expensive.

In addition, because the tubular member 72, including projections 56, isformed in a progressive die in the manner disclosed, the tubularcomponent which is to be welded is significantly less expensive incomparison with arrangements in which tubular stock material would beused. In addition, unlike tubular stock material, the tubular memberutilized in accordance with the present invention need not be seamwelded to form a complete cylindrical configuration, as can beappreciated from the cross-sectional view of FIG. 7.

FIG. 11 illustrates a further embodiment for manufacturing the panelspacer 10 illustrated in FIG. 1. In the embodiment of FIG. 11, the upperplate 26 is fixed to the upper end of spacer tube 12 by a projection orresistance weld at the same time that the lower base plate is projectionor resistance welded to the lower end of the spacer tube 12. In thisembodiment, the sheet metal is formed substantially as described above,with the exception that a plurality of upper projections 86 are formed(stamped) on an edge opposite the lower projections 56. Preferably, thestamping of the upper projections 86 are formed concurrently with thestamping of the lower projections 56. The projections 56 and 86 enablethe spacer tube 12 to be simultaneously projection welded to the baseplate 16 and the upper plate 26 for added efficiency in manufacturing apanel spacer in which the upper plate 26 is to be fixed to the spacertube 12.

As can be appreciated from FIGS. 9 and 11, for ease of manufacture, itis preferred for the openings 30 and 44 to be formed in the respectiveplate members 16 and 26 prior to the projection welding operation. Itshould also be noted that in FIGS. 9 and 11, two of the threeprojections 56 are illustrated in phantom for the purpose offacilitating an understanding of this invention, although only one ofthese three projections (the centered one) would ordinarily be visiblein the cross sections taken. The same is true with respect toprojections 86 in FIG. 11 and the projections illustrated in FIG. 18,discussed below. It should be understood that the three projections aremerely a preferred example, and that more or less projections may beprovided. Most preferably, at least three projections are provide toenable the roll formed tubular member to be balanced on the metal basemember 16.

FIG. 12 is similar to FIG. 1, but illustrates the panel spacer 10connecting the vehicle frame 102 to the panel 104 of a truck bed.

FIGS. 13-17 illustrate another embodiment of the method in accordancewith the present invention.

FIGS. 13-17 are similar to FIGS. 2-7 but, as can be appreciated fromFIG. 13, illustrates a method in which the interconnecting stripportions 160 connect adjacent portions of sheet metal towards thecenters of the adjacent edges of the respective portions of sheet metal.This is opposed to the strip portions 60 connecting the corners of thematerial as disclosed in FIGS. 2-7.

In addition, as can be best appreciated from FIGS. 15 and 16, in thisembodiment, both opposite edges the sheet metal are rolled towards oneanother to provide the tubular configuration of the spacer tube. This isin contrast to the prior embodiment, wherein it can be appreciated fromFIGS. 4 and 5 that only one edge is rolled towards the opposite edge.

As with the prior embodiment, the embodiment of FIG. 13 alsocontemplates that projections may be stamped on both the leading andtrailing edges of the sheet metal portion to enable both ends of theroll formed tubular structure to be projection or spot welded torespective metal members (e.g, as in FIG. 11). In addition, as with theprior embodiment, it is preferred for the adjacent edges forming seam170 in the roll formed tubular member (see FIG. 17) to be in adjacent orabutting relation with one another (the edges do not need to contact oneanother, although they may), and do not need to be welded. Welding wouldrequire an additional step and an additional expense that is preferablynot incurred in the method of the present invention.

FIG. 18 is a schematic representation of the projection or resistancewelding operation similar to that depicted in FIG. 9, but illustratingthat the upper electrode need not be particularly adapted to the shapeof the roll formed tubular member. Thus, the method is flexible as thesame welding apparatus can be used weld many different shapes of tubularmembers and base plate members.

The foregoing detailed description of the preferred embodiments of thisinvention has been provided for the purposes of illustration anddescription. It is not intended to be exhaustive or to limit theinvention to the precise embodiments disclosed. Other modifications andvariations may be evident to practitioners in the art when considered inreference to this disclosure.

What is claimed is:
 1. A method for making a spacer assembly,comprising: providing a portion of sheet metal having a plurality ofprojections formed thereon and extending from an edge thereof; rollforming said portion of sheet metal into a tubular configuration withsaid plurality of projections extending from an end of said tubularconfiguration; positioning said roll formed portion of sheet metal and ametal base member to which said roll formed portion of sheet metal is tobe welded in a discharge welding apparatus having a pair of electrodesso that the projections of said roll formed portion of sheet metalcontact a surface of said metal base member; providing a force so thatthe projections are disposed in forcible engagement with the surface ofsaid metal base member; and supplying an electrical current between thepair of electrodes and through said roll formed portion of sheet metaland said metal base member to enable the projections to reach a moltenmetal stage and be subsequently solidified so that the roll formedportion of sheet metal is welded to said metal base member; said methodcharacterized in that said plurality of projections are formed on saidportion of sheet metal before said portion of sheet metal is roll formedinto said tubular configuration.
 2. A method as in claim 1, wherein twoother edges of said portion of sheet metal are brought together by saidroll forming step to provide said tubular configuration, said two otheredges remaining unwelded to each other when said roll formed portion ofsheet metal is welded to said metal base member.
 3. A method accordingto claim 1, wherein said stamping results in an interconnecting portionbeing formed between said portion of sheet metal and a preceding portionof sheet metal, further comprising the step of: removing theinterconnecting portion between said portion of sheet metal and thepreceding portion of sheet metal after said portion of sheet metal isroll formed into said tubular configuration.
 4. A method according toclaim 1, further comprising the steps of: positioning a metal member onan edge of said roll formed portion of sheet metal opposite said edge onwhich said projections are stamped; fixing said metal member to saidopposite edge of said roll formed portion of sheet metal; wherein saidmetal member defines an opening, said opening being generally alignedwith a bore defined by said tubular configuration of said roll formedportion of sheet metal and an opening defined in the metal base member.5. A method according to claim 1, wherein said forming comprises astamping operation.
 6. A method according to claim 1, further comprisingforming a plurality of projections along an opposite edge of saidportion of sheet metal; engaging said projections along said oppositeedge with a metal member; wherein said force causes said projectionsalong said opposite edge to be disposed in forcible engagement with saidmetal member; and wherein said supplying of electric current causes saidprojections along said opposite edge to reach a molten stage, to besubsequently solidified to weld said roll formed portion of sheet metalto said metal member at said opposite edge, so that said metal memberand said metal base member are substantially simultaneously welded tosaid roll formed portion of sheet metal.
 7. A method according to claim1, wherein said metal base member is formed in stamping operation,including stamping of a hole therethrough, said hole being generallyaligned with a bore defined by said tubular configuration of said rollformed portion of sheet metal when said projections are disposed inforcible engagement with the surface of said sheet metal.
 8. A methodaccording to claim 6, wherein said metal base member and said metalmember are both formed in a stamping operation, including stamping ofrespective holes therethrough, said holes being generally aligned with abore defined by said tubular configuration of said roll formed portionof sheet metal when said metal member and said metal base member arewelded to said roll formed portion of sheet metal.